The only ammunitionrestrictions I am aware of are (or used to be) in Madison WI.
They referred to something about "Barbed Bullets"
My guess is that some city council member saw what a hollow-point looked like after striking a target and saw the expanded petals of the bullet as having "Barbs" on them and thought how it was not fair to the the criminalsthat are attacking youto be shot with one of these rounds because it may hurt them more than an FMJ.
25.035 BARBED BULLETS PROHIBITED.
(1) It shall be unlawful for a person to own or to have in her/his possession any barbed bullet in the City of Madison except as hereinafter provided. All barbed bullets possessed in violation of this section and all firearms possessed or used in connection therewith are unlawful property and shall be seized by any peace officer. Upon conviction of the person for a violation of this section, all such property shall be disposed of pursuant to Sec. 968.20(3)(b) of the Wisconsin Statutes.
(2) Barbed Bullet means any bullet that is designed to expand upon impact resulting in the bullet having evenly-spaced, pointed sharp hook or barb-shaped or other similar projections that extend beyond the original diameter of the unfired bullet.
And Teflon coated rounds are on the no-go list because they have the ability to slide past the weave in Kevlar.